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Sulfur is the third most abundant mineral element in the body. [21] The amino acids cysteine and methionine are used by the body to make glutathione. Excess cysteine and methionine are oxidized to sulfate by sulfite oxidase, eliminated in the urine, or stored as glutathione (which can serve as a store for sulfur). [21]
Non-toxic; in humans, it often substitutes for calcium. [11] sulfur: 16: 5: Sulfur is essential and ubiquitous, partly because it is part of the amino acids cysteine and methionine. Many metals that appear as enzyme cofactors are bound by cysteine, and methionine is essential for protein synthesis. Toxic in some forms. tantalum: 73: 1c
In animals, sulfur assimilation occurs primarily through the diet, as animals cannot produce sulfur-containing compounds directly. Sulfur is incorporated into amino acids such as cysteine and methionine, which are used to build proteins and other important molecules. [2]
The incorporation of these nonstandard amino acids is rare. For example, 25 human proteins include selenocysteine in their primary structure, [64] and the structurally characterized enzymes (selenoenzymes) employ selenocysteine as the catalytic moiety in their active sites. [65] Pyrrolysine and selenocysteine are encoded via variant codons.
Fluorine is used by a number of plants to manufacture toxins but in humans its only known function is as a local ... of life on Earth), sulfur ... amino acids ) 15 20 ...
The distinction between essential and non-essential amino acids is somewhat unclear, as some amino acids can be produced from others. The sulfur-containing amino acids, methionine and homocysteine, can be converted into each other but neither can be synthesized de novo in humans. Likewise, cysteine can be made from homocysteine but cannot be ...
Sulfur is an essential element for all life, almost always in the form of organosulfur compounds or metal sulfides. Amino acids (two proteinogenic: cysteine and methionine, and many other non-coded: cystine, taurine, etc.) and two vitamins (biotin and thiamine) are organosulfur compounds crucial for life.
CBS occupies a pivotal position in mammalian sulfur metabolism at the homocysteine junction where the decision to conserve methionine or to convert it to cysteine via the transsulfuration pathway, is made. Moreover, the transsulfuration pathway is the only pathway capable of removing sulfur-containing amino acids under conditions of excess. [9]